Will Bitcoin XT be traded as a new coin separate from btc?

no, XT is just fork of core with some added features like BIP: 101 (incerase block size), BTC will remain same and there will be no new coin, if this XT madness will even happen.

BIP101: https://github.com/gavinandresen/bips/blob/fd99a8ce04dbad96fb275e0300a7ee669e70f418/bip-0101.mediawiki

more info is here: https://github.com/bitcoinxt/bitcoinxt/blob/master/README.md

so no worries, I was also confused, but only way how to understand is at least little bit is reading and reading of sources posted above.